Ellipsograph



Aug. 23, 1932. J, E 1,872,973

ELLIPSOGRAPH Filed Jan. 4, 1928 2 Sheets-Sheet 1 IN VENT OR John JKi tfel Aug. 23, 3932.

J. J. KITTEL ELLIPSOGRAPH Filed Jan. 4. 1928 2 Sheets-Sheet 2 John lKiZfeZ INVENTOR Patented Aug. 23, 1932 UNITED STATES PATENT? "OFFICE JOHN J. KITTEL, OF ST. ALBANS, NEW YORK, ASSIGNOR OF ONE-EMF TO ERNEST w. BEEBE, OF EAST ORANGE, NEW JERSEY ELLIPSOGRAIH Application filed January 4, 1928. Serial No. 244,390.

part of this specification illustrate certain.

practical embodiments of the invention, but

it is to be understood that the structure may be modified and changed without departure from the broad spirit and scope of the invention.

Figure 1 is a side elevation of one form of the compass indicating in dotted lines certain adjustments showing also how the device may be converted into a double acting instrument.

Figure 2 is a plan view of the instrument.

Figure 3 is a horizontal sectional view as on substantially the plane of line 3-3 of Figure 1.

Figure 4 is another horizontal sectional view as on substantially the plane of line 4-4 of Figure 1.

Figure 5 is a broken vertical sectional view on an enlarged scale substantially on the plane of line 5-5 of Figure 2.

Figure 6 is a detail sectional view as on the plane of line 6-6 of Figure 5.

Figure '7 is an enlarged brokensectional detail of the adjustment screw as on line 77 of Figure 2.

Figure. 8 is a broken sectional detail as on the plane of line 8-8 of Figure 3.

Figure 9 is a broken and sectional detail of the step which can be applied to the cen ter post to securely hold it against turning. Figure 10 is a cross section of the same as on line 1010 of Figure 9. Figure 11 is a broken detail showing how 'the instrument may be used .for drawing particularly small figures. 4

Figure 12 is a side view illustrating certain modifications and showing the device built as a double instrument.

Figure 13 is a broken sectional view of a 55 modification having an internal gear for the fundamental gear.

Figure 14 is a diagrammatic view illustrating the hypocycloid curve generated by this type of gearing.

Figure 15 is a'diagrammatic representation of the forming of two reverse scrolls to lay out a heart cam.

Figure 16 is a diagram illustrating the forming of reversely curved cam shapes.

Figure 17 is a diagram showing the forms of two reverse epicycloids.

Figure 18 is a view illustrating diagrammatically formation of eccentric and concentric elliptical and circular figures drawn with the compass shown in Figure 1.

The instrument is in the general nature of a compass having the two legs, a centering post 20 and a rotating arm 21, carrying the pen 22, pencil or other scriber. For holding the center post against turning, there is shown a shoe23 (Figures 9 and 10) having a parallel sided split socket 24 in which the similarly flat sided lower end portion 25 of the post is detachably secured b the clamping screw 26, said shoe having a ocat-. ing center 27 and offset a sufiicient distance from that, a holding center 28. This shoe is particularly desirable when describing .the larger curves, but is so constructed that when not needed, it may be immediately removed.

The arm which carries the scriber has a radially sliding movement over the center post, being shown for the purpose longitudinally slotted at 29-to slide closely over the post.

In Figures 1 and 5, this radially traveling arm is shownmade in two parallel members 21 and 21a secured together in spaced relation by rivet studs 30, both slotted to slide over the center pin and held to a definite lane of movement thereover by a positioning guide block 31 rigidly secured on the post tween positioning washers 33 fixed on the Adjustment of the scriber relative to the arm is effected in the illustration by forking the upper end of the scriber at 34 to slide over the shank of a thumb screw 35, Figures 5 and 6, which clamps the scriber against the fiat: side 36 of a horizontal stud 37 jour v.naled in bearings provided in the dependent spring cheeks 38, said stud having a head 39 at one end bearing against the outer face of one cheek and carrying a thumb nut 40 at its opposite end bearing against the outer face of the other check. It will be seen that by means of thumb screw 35, the scriber may be secured in vertically adjusted relation and the thumb screw 40 enables the scriber being secured at different radial distances, as shown particularly in Figures 1 and 11.

These views illustrate further that the dependent cheeks 38 may have two sets of bearing openings 41 for the swivel stud 37 of the scriber at different radial distances from the general center, which may be used for larger or smaller curves, permitting the more advantageous setting of the pen or scriber for such curves.

The radial shifting of the scriber arm is effected by a system of sun and planet gearing and a variable throw crank connection between the planetary gear and scriber arm. The fundamental or sun gear is shown at 42 adjustably fixed on the center post by set screws 43, and the planetary gear is indicated at 44 carried by a shaft 45 journaled in the top and bottom plates 46, 47 of a frame which is rotatably mounted on the post and turned by a thumb wheel 48. The generating or planet gear 44 is indicated as of half the sizeor as having half the number of teeth of the fundamental gear and as coupled to the latter through an intermediate pinion 49 journaled'on a spacing stu'd 50, which holds the plates of the rotary frame together.

The variable crank connection is provided in the illustration by a block 51, pinned at 52 on the lower end of shaft 45 and carrying guide rods 53, 54, Figure 3, working through the upstanding cars 55, 56, on the ends of a horizontal plate 57, fixed on the upper end of a pintle 58 journaled in the outer end of the scriber arm.

The rods 53 and 54 are shown in Figure 3 shaft 45 and as as located on ohpxposite sides of the axis of ed in opposite end portions of the block 51 by set screws 59. The pintle 58 is shown surrounded by a s acing collar 60, which in the form illustrate in Figure 5,-

rotates between the upper and lower plates of the radial arm and in the single plate form of arm shown in Figure 12, sim ly bears on top of the arm. A friction re ucing shoulder or washer 61 is shown in Figures 1 and 5 interposed between the crank frame 57 and the A top plate 21a of the radial arm.

If the axes of the lanetary pinion 44 and the crank pin 58 are rought into alinement, it will be evident that the turning of the crank connection by the planetary pinion will have no effect on the scriber arm, as the pin 58 will then be turning on the same axis as the shaft 45. If on the other hand, these centers are offset, as they are indicated, for instance, in Figures 1, 5 and 12, the rotation of the planet pinion in its movement about the fundamental gear will, to the extent of such ofi'set, impart corresponding radial movements to the scriber.

In the present disclosure, the relative concentricity or eccentricity of. the planetary axis and crank axis are governed by a thumb screw 62 journaledin the upstanding arm 55 of the crank frame, Figure 7, the-rod 54 having a fine screw thread to take the same and being held in its adjusted relation by a coiled spring 63 interposed between the back of the head of this screw and the bearing lug 55. This spring thrusts the thumb nut 62 outwardly, holding the head or shoulder 64 at the inner end of the same frictionally engaged against the inside face of the bearing lug 55. Adjustment of the thumb nut 62,

therefore, determines the orbit or non-orbital movement of the crank center 58 and hence the in and out radial movement or lack of radial movement of the scriber during the orbitaltravel of the gear frame and scriber arm about the center post.

Preliminary setting and adjustment of the generating pinion 44 is provided for in the I illustrated construction by a knob 65 on the upper end of the shaft 45 and a dial 66 on the v same shaft whose markings may register with a scale mark 67 on the top plateof the frame. The center post is shown as having a button or finger-hold 68 on the upper end of the same to aid in positioning and in holding the same against rotation.

Where a single scriber is employed as shown in full lines in Figure 1, the frame may be counterbalanced by a suitable weight 69 secured diametrically-opposite the planetary pinion and of a'weight to approximate that of the planetary gearing, crank motion .and scriber. When a second scriber is used in the same instrument, this counterbalancing is unnecessary, as the extra pinions, crank movement and scriber at one side will balance the the center post and rotating the generatingweight of these parts at the opposite side. In Figure 12, this balanced condition is present, there being two complete planetary move ments, one diametrically opposite the other; and with such a construction, two complete figures, ellipses, circles or other designs, may be simultaneously created by simply holding frame, by the handle 4 8, or otherwise Thus, a circle and an ellipse may be both produced at the same time. Parallel circles or ellipses may be produced by simply swinging the scribers on their supporting centers either in or out, as indicated in Figure 1.

Figure 18 indicates at'the left how different size ellipses may be produced from relatively large to quite small sizes, and at the right in this view, circular as well as elliptical outlines are illustrated. These views illustrate furthermore how the rela tions between the major and the minor axes of the ellipses may be varied to produce either long narrow forms of ellipses, as at the right in this view, or the more nearly circular forms of elliptical figures.

True epicycloid curves may be produced, as indicated at in Figure 17, or outwardly convexing and inwardly concaving curves, as shown at 71 and 72 in Figure 16, all by proper setting and manipulation of the instrument. Also scroll curves, such as shown at 7 3 in Figure 15, may be drawn with the instrument and two such curves may be matched as indicated at 74 to form atrue heart cam.

By using an internal gear for the fundamental stationary fgear, as shown at 75 in Figure 13, other effects may be obtained such as the curve indicated at 7 6 in Figure 14. In the Figure 13 construction, the generating gear 44a works insidethe internal gear and the orbital movement of the same is 'efiected by means of an outstanding handle 77 provided as an extension of the upper plate 46a of the gear frame, which in this case is swivelled on the post wholly below the fundamental gear.

The instrument .is' relatively small. and compact and can be handled practically as easily as an ordinary compass by various adjustments of the scriber and of the crank connection. Many different sizes and forms of curves may be produced. The dials on the generating pinions enable quick setting of the instrument to major and minor axis positions. The step which can be applied to the foot of the post is of great advantage in drawing large curves, but the same can be quickly removed when small curves, such as indicated in Figuresll and 18,are to be drawn, and in the latter event, the post is easily held against turning by means of the knurled finger button 68.

' The point 28 may be removable from the step, Figure 9, thus rendering it unnecessary to take olf the step when it is desired to rotate the post. When drawing circles, the adJusting nut 62 is preferably turned to bring the centers 58 and 45, Figure 5, in alinement. In drawing the small figures, the scriber operates in between the center of the generating gear and the fundamental center at 20, as indicated in Figures 5 and 11, producing true ovals and enabling the instrument to be operated equally as well in either direction from any starting point.

What is claimed is:

1. An elliptograph compass, comprising a center post, a fundamental gear fixedly carried thereby, a gear frame rotatable on and about the post, a generating gear carried by said frameand rotated from the fundamental gear 1n said generating gears orbital travel about the post, a scriber arm rotatable about and radially shiftable relative to the center post, a crank pivoted to said scriber arm and a variable throw connection between the generating gear and said crank, said crank be- 1ng inthe form of a yoke and the variable connection including a block rotated by the generating gear, a screw rod carried by said block and engaged with said yoke and an adjusting nut on the yoke and engaged with said screw rod.

2'. An elliptograph compass, comprising a center post, a scriber arm pivotally connected with and radially movable in respect to said post, a yoke having a pivotal connection with said scriber arm, a fundamental gear fixedly carried by the post, a generating gear rotatable bodily about the fundamental gear and rotated by said fundamental gear as it travels about the same, a head rotated by said gencrating gear and a variable screw connection between said head and yoke for setting the pivotal center of the yoke in different relations to the axis of the head.

3. In an instrument of the character disclosed, a fundamental gear, a generating gear bodily rotatable about said fundamental gear and rotated therefrom, a scriber arm rotatable about and radially shiftable relative to the axis of saidfundamental gear, a crank connection between the generating gear and scriber arm and including a fine screw by which the throw of the crank may be accurately varied, a dial for the generating gear and a knob associated with said dial for turning said gear.

. 4. In an instrument of the char cter disclosed, a center post, a scriber ar confined to said post and radially s'hi ble in respect thereto, a yoke swivelled to said scriber arm, a yieldingly held thumb nut mounted in said yoke, a screw rod slidable in said yolk and engaged with said nut to be slid thereby, a generating gear, means mounting the same for bodily rotation about the post, a shaft driven by said gear, means for connecting the screw rod to said shaft at right tably angles thereto and a fundamentalgear carried by the post for effecting rotation of the generating gear in the travel of the same. about the post.

5. In an instrument of the character d1sclosed, a center post, a sun gear thereon, a frame rotatably confined to sa1d post, a planet gear journaled in said frame and operated from the sun gear as the frame moves about the post, a scriber arm rotatable about and radially shiftable with respect to the post in spaced relation below the frame, a crank swivelled to "the scriber arm and operatmg in the space between the frame and scriber arm, the planet gear having a shaft journaled in the frame, a rod carried by said shaft at right angles thereto and having a drlving engagement with the crank and screw means for relatively shifting said rod and crank to predetermine the relation of the axes of the sun gear and pivotal center of the crank. 6. In an instrument of the character disclosed, a center post, a sun gear thereon, a frame rotatably confined to sa1d post, a planet gear journaled in said frame and operated from the sun gear as the frame moves about the post, a scriber arm rotatable about and radially shiftable with respect to the post in spaced relation below the frame, a crank swivelled to the scriber arm and operating in the space between the frame and scriberarm.v the planet gear having ashaft journaled in the frame, a rod carried by said shaft at right angles thereto and having a driving engagement with the crank, screw means for relatively shifting said rod and crank to predetermine the relation of the axes of the sun gear and pivotal center of the crank and an indicator directly over and connected with the planet gear for enabling preliminary setting of the same.

7. In an instrument of the character disclosed, a center post, a scriber arm radially shiftable with respect to and rotatable about the post, a frame confined to and rotatable about the post, a sun gear on the post, a planet gear on the frame and rotated from the sun gear in the travel of the frame about the post and a variable crank throw connection between the planet gear and scriber arm, in-

rating gear for rota movement about the fundamental gear an a variable crank connection from the generating gear to the v eluding a rotatable member swivelled to the scriber frame and means for effecting the shifting of the axis of said rotatable member in a straight line across the axis of the planet gear.

8. In combination, a center post, a scriber arm confined to and rotatable thereabout and shiftable radially in respect thereto, a scriber carried by said arm and adapted to operate up to positions immediately adjacent the center post, a fundamental gear carried by the center post, a generating gear confined to and bodily operable about the center post and rotated from the fundamental gear in such movements a frame for mounting the gene- 

